Thermal gelation properties of carboxymethyl cellulose and bentonite-carboxymethyl cellulose dispersions: Rheological considerations

Viscosity measurements show that for both CMC solutions and bentonite-CMC dispersions sudden changes in viscosity occur as the temperature increases. The viscosity is found to decrease below a critical temperature which corresponds to a cloud point or gelation temperature. Above this later, the viscosity increases dramatically with temperature. Hydrophobic interaction is postulated to be the cause of gelation.